Refrigerating machine



Dec. 7, 1937. g STEENSTRUP I 4 2,101,656 I REFRIGERATING MACHINE FiledJan. 22, 1955 2 Sheets-Sheet l I Inventory ChHstiah Ste'enstrmp,

is Attbr-ney Dec. 7, 1937. C.STE:NS RUP 1 2,101,656

I REFRIGERATING MACHINE Filed Jan. 2,2, 193s 2 Sheets- 8116912 InventomChristian Steenstrup,

His AttOF'neld.

Yawn De f 1,1937

UNITED STATES was.

PATENT- OFFICE aamrcnaa'rma momma Christian Steenstrup, Schenectady, N.'r., as-

signor to General Electric Company, a corporation of New YorkApplication January 22, loss, Serial No. 2.912

18 Claims. (01. 62-99) My invention relates to refrigerating machines.

/ In many types of refrigerating machines and particularly in thosedesigned for domestic use,

it is necessary to make provision for the storage 6 and preservation ofalarge variety of perishable articles and it is also desirable toprovide appa ratus for freezing ice and the like therein. Someperishable articles, such as me at, which are to be stored for arelatively long period of time can 10 be most easily preserved bymaintaining them at a temperature below 32F. Other articles, such asmilk, should be maintained at a somewhat.

higher temperature. In addition, it is necessary to make provision forthe storage of vegetables of various kinds, which also need' not be keptat' a temperature below 32" F., but which aresubject to rapiddeterioration through dehydration unless kept under proper conditions oftemperature and humidity. .In commercial cold storage establishments itis possible to provide a large number of separate refrigeratingmachines, each being designed to maintain the particular temperature andhumidity conditions required by the particular variety of articles tobepreserved therein. It is obvious, however, that such an arrangement isnot economically feasible for domestic use or for use in smallrestaurants, and the like.

erating device and that the entire apparatus be preferably housed in asingle cabinet.

Refrigerating machines of the primary-sec ondary type are particularly.adapted for the purpose described. In refrigerating machines of theprimary-secondary type a primary refrigerant syst'em o'r circuit isprovided which includes a primary evaporator supplied with liquidrefrigerant from a suitable source or refrigerant 4o circulating deviceof any. of the wellknown types.

The secondary refrigerant system or circuit also includes anevaporator.- Ifhe refrigerant pass sages of the two refrigerant circuitsare not in communication with each other, but "portions of 1 the tworefrigerant-circuits are, however, ar-

ranged in heat exchanged relationship. so. that the primary evaporatorabstracts heat. from the refrigerant contained in the secondaryrefrigerant circuit. Because of the independence of the circulatorysystems of the two refrigerant cir--.

cuits it is possible to maintain the evaporator contained-ineach'circuit at a different temperature from the other. i x

It is an object of my invention to provide a- 6 refrigeratingmachinehavin'g a single refrigerant Limitations of space'and cost makeit necessary that the refrigerating apparatus for in- 3o stallations ofthis type contain but a. single refrigscription proceeds and thefeatures of novelty which characterize my invention will be pointedoutwith particularity in the claims annexed to 15 .and forming a part ofthis specification.

For a better understanding of my invention reference may be had to theaccompanying drawings, in which Fig. 1 is a front elevation partly insection -of a refriger lng machine embodying 20 my invention; Fig. 2 isside elevation partly in section of the refrigerating machine shown inFig. 1.; Fig. 3 is an exploded view of the refrigerating machine shownin Fig. 1 the lower portion thereof being partly cut away; and Fig.1! isa sectional detail view of a modified form of heat conducting memberwhich maybe used in the refrigerating machine shown-in Figs. 1, 2, and3. Referring to the drawings,' in Fig. 1 I have shown ja refrig'eratingmachine embodying my 30 invention having a smooth walled rectangularcabinet made up of separable upper and lower portions l 'andZ,respectively.. The upper por- -tion I of'the cabinet is provided with anouter sheet metal shell 3 and has a rectangular food storage or freezingcompartment 4 formed therein. The side wallsand top of the freezingcompartment 4 are surrounded by heat insulation ii.

- 'I'he lower portion 2 of the cabinet, which sup ports the upperportion: I, is provided with an. 40

outer sheetmetal shell'B, and has a rectangular food storage or coolingcompartment I formed therein. The side walls and bottom wall of 'thecompartment I are surrounded by heat 'ins'ula tion- 8. The metal shell 3is provided with a 5 downwardly extending rectangular flange Ia,

which surrounds the upper periphery of the metal I shell 6,}therebyforming aflrm telescopic Joint between the" upper and lower portions Iand 2 respectivelyf'of the cabinet, and effectively pre- 50 ventstheirrelative lateral displacement. A rectangular rubber gasket 9 restson the inturned. rectangular upper edge of the metal shell 8 and isfirmly pressed thereon by the weight of the upper portion l of thecabinet. An air-tight so joint is thus formed between the upper andlower portions of the cabinet and in that way the ingress of air to the.space between them is. prevented. It is necessary thus to excludemoistureladen-air from the space between the walls of the cabinetcontaining insulation both to prevent the formation of frost therein andalso to prevent the deposit of moisture in the insulation, because theinsulation is usually made of some dry fibrous material, the heatinsulating properties of whicha're radicallyreduced when it absorbs asubstantial amount of moisture.

' The freezing compartment 4 is provided with a metallic liner llcooperating with a corrugated metal sheet 12, which surrounds the linerII on four sides thereof to form a refrigerant,evaporator Ill associatedwith the freezing compartment 4.. The inwardly projecting ridges of thecorrugations formed in the sheet I2 are in contact with the smooth sheetmetal liner Ii and are welded; brazed or otherwise secured theretothroughout their length. The transverse corrugations in.the plate i2cooperate with the liner II to form refrigerant passages l3 which areconnected at their opposite ends with a header M, the latter beingformed by opposed portions of the liner l I and the metal sheet l2.

An evaporator structure consisting of a smooth cooled by natural draft.I Liquefied refrigerant leaves the condenser I! through a conduit I8 andpasses through a flow controlling float valve l9 flowing therefromthrough a conduit 20 to an inlet 2l in the side of the evaporator Ill.The

liquid refrigerantis thus injected into the evaporator lll by'the inlet2| from the conduit 20 and reclrculates through the refrigerant passagesl3 of the evaporator l0 and its header l4. Liquid refrigerant in therefrigerant passages I3 is vaporized by the absorption of heat fromarticles contained in the freezing compartment 4 and the upper wall ofthe lower compartment I and the bubbles of vaporized refrigerant flowtherej through to the header [4 where they are collected above the levelof the liquid refrigerant therein. The vaporized refrigerant collectedin the header I4 is returnedto the compressor in. the casing l5 througha suction line 22, which is connected to the top of header l4 and above.the level of the liquid refrigerant therein.

The cooling compartment 1 has a metallic liner 26, which is surroundedon four sides by a metal sheet '21 provided with transverse corrugationscooperating with the liner 28 to form the refrigerant passages of asecondary evaporator or container 25 associated with the coolingcompart- -ment I and constituting a secondary refrigerant system. Theinwardly extending ridges of contact with the smooth sheet metal liner26 and are welded, brazed or otherwise secured thereto throughout theirlength. A body of liquid vaporizable refrigerant is contained in thesecondary side portions thereof, and as it absorbs .heat

from articles contained in the cooling compartment I it is vaporized,the bubbles of vaporized refrigerant passing upwardly through thevertical refrigerant passages of the evaporator 25 and being collectedin the upper horizontal portion 28 thereof. d

The top of the secondary evaporator 25 and the bottom of the primaryevaporator ID are arranged adjacent the opening in the interior of therefrigerator cabinet between the freezing compartment 4 and the coolingcompartment 1 and a corrugated resilient metal plate 29 is placedbetween the top of the secondary evaporator 25 and the bottom of theprimary evaporator I0, which plate together with the top of thesecondary evaporator 25 and the bottom of the primary evaporator l0 forma dividing wall between the freezing compartment 4 and the coolingcompartment I. The corrugated metal plate 29 thus forms a resilient heatconducting member between the primary and secondary evap'orators tofacilitate heat exchange between the two refrigerant circuits.

As best shown in Fig. 3, the corrugations in the metal plate arearranged transversely of the parallel corrugations in sheets l2 and 21in order to improve the contact between adjacent surfaces thereof. Theclearance between the sheets 12 and 21 is made slightly less than theunstressed depth of the corrugations in the metal plate 29, so that whenthe respective parts are in position the metal plate 29 will be somewhatflattened, accordion fashion, thus insuring a tight contact between theabutting surfaces of sheets I2 and 21 and the metal plate 29. I havealso found it advantageous to cover these abutting surfaces with a thinfilm of grease which improves the contact and aids in preventing theformation of frost therebetween.

ator 25 is liquefied and then drains back to the lower portion thereofwhere it again absorbs heat from articles stored in the coolingcompartment and is vaporized. As best shown'inFigs. 1 and 3, the topportion of evaporator 25 slopes to one side so as to facilitate thereturn flow of liquid refrigerant therefrom to the lower portion of theevaporator.

The heat conductivity of the plate 29 is pro- I portioned by varying itsconstituent material, the

temperature of the primary evaporator It be substantially lower thanthat of the secondary evaporator 25 for the proper operation of themachine. The'primary evaporator it should be maintained at a temperatureof from 0 to 10 FJwhile the temperature of the secondary evap'-orator-25 should be maintained about 32 F.

of these evaporators with relation to the proper preservation of thematerials contained in the compartments 4 and I, respectively, ispointed out. more in detail below.. The desired diflerence intemperature between the evaporators l0 and 25 may also be attained byproportioning the amount of liquid refrigerant contained in each ofthem. used as the-refrigerant in both evaporators, the amount of liquidrefrigerant in the secondary evaporator 25 may be proportioned withrespect to its total volume in such manner that only the lower portionsof the refrigerant circulatory passages of the secondary evaporator 25formed between the sheets of metal 25 and 21 are filled with liquidrefrigerant. Then, since the portion of the evaporator containing liquidrefrigerant performsthe. major part of: the cooling, the total amount ofheat dissipated from the cooling compartment I is decreased and theaveragetemperature prevailing in the cooling compartment is increased.

I have thus provided meansfor abstracting heat from the contents of boththe freezifig and cooling compartments 4 and I in such manner that eachis maintained at its appropriate tem- 29 described above. The resilientheat conducting member 30 comprises a body of thermally conductingmasses 3i, which may. be metallic shot of spherical configuration madeof lead or steel, or the like, and which are bonded together by aresilient matrix of rubber, or some similar binding material. Themetallic spheres areso arranged that their adjacent peripheral portionsare in direct contact thus forming a heat transfer path between thesheets i2 and 21 while the rubber matrix allows a suflicien-t resiliencein the member at that its upper and lower surfaces 5 will form a tightcontact with the adjacent irregular surfaces of the sheets It and It. Itwill be obvious to those skilled in the art that other forms ofresilientheat conducting members may be substituted for the forms whichI have illustrated. The ai'nountof heat transferred through the memberI0 maybe limited, for the purposes noted above, by varying the number ofthermally conducting masses 3| and the distance between this upperportion I of the cabinet 'may be easily attached and removed from thelower portion 2 for purposes of sssembiyand repair. The separablearrangement of the upper and lower portions l and 2'01' the cabinetand-the corrugated 'plate 29 is best shown'in'Fig. 3. The secondaryevaporator 25 isarranged to be-easiiy inserted or removed through theopening in the. top of insulatingcasing I thus further taking advantageof the separable construction of the cabinet.

As will be seen from an inspection of Fig. 2, the" freezing and coolingcompartments 4 and I are If sulphur dioxide, for example, is

and I have found- 40 tively, in the front walls thereof which may beclosed by thedoors 34 and 3 5. The openings 32 and 33 provide aconvenient means of access to their respective compartments. Cuts ofmeat,

' or other perishable articles which should be maintained at atemperature of below 32 F., usually within the range of from 0 F. to 10F., in order to 'ment 4. Trays of water to be frozen, ingredientsfor icecream and the like, may alsobe placed in the freezing-compartment 4. Thecooling compartment I is provided with horizontal shelves 36 which aresupported on the projections 31 formed on the interior lateral walls ofthe metallic liner 26. Bottles of milk, vegetables and the like, may bepreserved in the cooling compartment I at a temperature above 32 'F. andbelow F. F. to be a desirable average. operating temperature. It will benoted that the secondary evaporator 25 surrounds four walls of thecooling compartment I thus providing a relatively large cooling area inproportion to the cubic contents of the cooling compartment I. Thus, itis possible to cool the contents of compartment I witha relatively smalltemperature differential, that is in the order of about .5" F..- betweenthe'compartment and the secondaryevaporator 25. The use of an evaporatorsurrounding at least four walls of the compartment I has a furtheradvantage in maintaining a small temperature differential between thecontents of the compartment and the evaporator which cools it. Thisadvantage results from thefact that heat leaking into the compartment Ithrough the insulated walls 8 thereof. is intercepted on at least foursides by the evaporator 25. This heat,

which leaks into the cabinet, is thus absorbed directly by theevaporatorsurfaces. In the case of a conventional type of refrigeratorin which a large compartment is cooled by a relatively small and compactevaporator, heat," which leaks into the cooling compartment through thewalls thereof, must be transferred through the air contained in thecompartment to the evaporator thus further increasing the temperaturedifferential between the air in the compartment and the.

evaporator. By means of the arrangement described, the interior walls ofthe evaporator 25 i 3 I provided with alined openings .32 and 33, respecmay be maintained at a temperature above 32 F. and thus frosting of thewalls of the evaporator 25 and hence dehydration of the contents of thecooling compartment I, is avoided. Dehydration of vegetables and similararticles is of prime importance to their'proper preservation, sincedehydration is one of the principal causes of their wilting and takingon an unpalatable appearance. In the illustrative form of myinventionthe primary evaporator I0 is also provided with a relatively largecooling area in proportion to the cubic contents of the freezing'chamber4 in order to reduce the frosting thereof. That is, if we assume a fixedrate of dehydration, the thickness of the layer of frost formed on theevaporator lfl'will be inversely proportional to its area.

While I have shown a particular embodiment tion to be limited to theparticular construction shown and described and I intend in the appendedWhat I claim as new and desire to secure by Letters Patent of the UnitedStates is:

. of m'yjnvention inconnection with a'compression refrigerating machine,I do not desire my invenwith said cooling compartment for cooling-the l.A refrigerating machine comprising a heat insulated cooling compartment,a separable heat insulated freezing compartment mounted adjacent saidcooling compartment, said compartments being mounted as a unitarystructure and the exterior wall of said compartments defining a smoothwalled rectangular cabinet, means including a refrigerant evaporatorhaving a portion thereof associated with saidfreezing compartment forcooling the contents thereof to a relatively low temperature, meansincluding a second refrigerant evaporator having a portion thereofassociated means including a refrigerant evaporator having a portionthereof associated with said freezing compartment for cooling thecontents thereof to a relatively low temperature, means including asecond refrigerant evaporator having a' portion thereof associated withsaid cooling compartment for cooling the contents thereof to atemperature above freezing, and means including a portion of the firstmentioned evaporator for abstracting heat from refrigerant contained insaid second evaporator.

3. A refrigerating machine comprising a heat insulated coolingcompartment, a separable heat insulated freezing compartment supportedon the top of said cooling compartment and cooperating therewith to forma unitary cabinet structure, means including a refrigerant evaporatorhaving a portion thereof associated with said freezing compartment forcooling the contents thereof to a relatively low temperature, saidevaporator having a second portion thereof extending along the bottomofsaid freezing compartment, and means including a secondary refrigeratingapparatus having a portion thereof associated with said coolingcompartment for cooling the contents of said cooling compartment to atemperature above freezing, said secondary refrigerating apparatushaving a refrigerant passage extending along the top ofsaid coolingcompartment in heat exchange relationship with the adjacent portion ofsaid first mentioned evaporator. I V

4. A refrigerating machine comprising heat insulated cooling andfreezing compartments,

means including a refrigerant evaporator having a portion thereofassociated with said freezing compartment for cooling the contentsthereof to a relatively low temperature, said evaporator having a secondportion thereof extending along the exterior side of oneof'the walls ofsaid freezing compartment, means including a secondary "refrigeratingapparatus having a portion thereof frigerating apparatus sage extendingalong the top of said cooling com- 5. A refrigerating machine comprisinga heat insulated cooling compartment, a separable heat insulatedfreezing compartment mounted on top of the said cooling compartment,means including a refrigerant evaporator having a portion thereofassociated with said freezing compartment for cooling the contentsthereof to a relatively low temperature, said evaporator having a secondportion thereof extending along the bottom of said freezing compartment,means including a secondary refrigerating apparatus having a portionthereof associated with said cooling compartment for cooling thecontents of said cooling compartment to a temperature above freezing,said-secondary refrigerating apparatus having a refrigerant passageextending along the top of said cooling compartment, and means includinga corrugated sheet of resilient heat conducting material fortransmitting heat from said secondary refrigerant apparatus refrigerantpassage to the adjacent portion of said first mentioned evaporator.

6. A refrigerating machine comprising a heat insulated coolingcompartment, a separable heat insulated freezing compartment mounted onthe top of said cooling compartment, means includa refrigerantevaporator having a portion thereof associated with said freezingcompart ment for cooling the contents thereof to a relatively lowtemperature, said evaporator having a secondportion'thereof'extendingalong the bottom of said freezing compartment, means including asecondary refrigerating apparatus having a portion thereof associatedwith said cooling compartment for cooling the contents thereof to atemperature above freezing, said secondary rehaving a refrigerantpassaid secondary refrigerating apparatus refrigerant passage to theadjacent portion of said first mentioned evaporator.

7. A refrigerating machine comprising separable freezing and coolingcompartments mounted adjacent each other, a rectangular metallic linerforsaid freezing compartment, a refrigerant evaporator extending aboutat least four sides of said liner, an insulating casing surrounding saidfreezing compartment and having an aperture therein exposing a portionof an exterior side of said refrigerant evaporator, a rectangularmetallic liner for said cooling compartment, a second refrigerantevaporator extending aboutat least four sides of said last mentionedliner, an insulating casing surrounding said cooling compartment andhaving an aperture therein adjacent the aperture in the first mentionedinsulating casing exposing a portion of an exterior side of saidsecondary refrigerant evaporator, and means including a resilient heatconducting member for transmitting heatbetween the exposed portions ofsaid evaporators.

8. A refrigerating machine comprising separable freezing and coolingcompartments mounted adjacent each other, said freezing compartmenthaving a rectangular metallic liner, a corrugated metallic sheetsurrounding said liner on at least four sides, said liner and said sheetdefining a refrigerant passage between the juxtaposed faces thereof, aninsulating casing surrounding said freezing compartment and having anaperture therein exposing a portion of an exterior surface of saidrefrigerant passage, a rectangular metallic frigerant passages.

9. In a refrigerating apparatus having a primary refrigerant evaporatorand a secondary refrigerant evaporator containing a body of liquidrefrigerant, means for supplying liquid refrigerant to said primaryevaporator and means including'a resilient heat conducting memberarranged between said primary and secondary evaporators in heat exchangerelationship therewith for transferring heat from the refrigerant insaid secondary evaporator to the refrigerant in said primary evaporator.

, 10. In a'refrigerating apparatus having a primary refrigerantevaporator and a secondary refrigerant evaporator containing a body ofliquid refrigerant, means for supplying liquid refrigerant to saidprimary evaporator, and means in, cluding a resilient heat conductingmember comprising a body of thermally conducting masses arranged betweensaid primary and secondary evaporators in heat exchange relationshiptherewith for transferring heat from the refrigerant in said secondaryevaporator to the refrigerant in said primary evaporator.

11. In a refrigerating apparatus having a pri mary refrigerantevaporator and a secondary refrigerant evaporator containing a body ofliquid refrigerant, means for supplying liquid refrigerant to saidprimary evaporator, and means including a corrugatedsheet of resilientheat conducting material arranged between said primary and secondaryevaporators in heat exchange relationship therewith for transferringheat from the refrigerant in said secondary-evaporator to therefrigerant in said primary evaporator.

12. In a refrigerating apparatus having a primary refrigerant evaporatorand a secondary re-' frigerant evaporator containing a body of liquidrefrigerant, means for supplying liquid refrigerant to said primaryevaporator, and means ineluding a resilient heat conducting membercomprising a" body of metallic spheres bonded together by rubberarranged between said primary I and secondary evaporators in heatexchange relationship therewith for transferring heat from therefrigerant in said secondary evaporator to l the refrigerant in saidprimary evaporator.

13. A refrigerating machine comprising heat insulated freezing andcooling compartments having an opening therebetween, means including aprlmary evaporator having a portion thereof associated with saidfreezing compartment for cooling the contents thereof to a relativelylow temperature, said. primary evaporator having a further portionthereof extending across said open .ing, means including a secondaryrefrigerating apparatus provided with a secondary evaporator having aportion of relatively large area associated with said coolingcompartment for cooling the contents of said cooling compartment to a 4temperature above freezing and for maintaining a relatively smalldifferential in temperature be 75 tween said secondary evaporator andthe contents of said cooling compartment to prevent dehydrationthereof', said secondary refrigerating apparatus also including arefrigerant passage in heat exchange relationship with the portion ofsaid primary evaporator extending across said opening between saidcompartments.

14. A refrigerating machine comprising a heat insulated coolingcompartment, a separable heat insulated freezing compartment supportedon top "of said cooling compartment and cooperating therewith to form aunitary cabinet structure, means including a refrigerant evaporatorhaving .a portion thereof associated with said freezing compartment forcooling the contents thereof to a relatively low temperature, saidevaporator hav ing a second portion thereof extending along the bottomof said freezing compartment, means including a secondary refrigeratingapparatus having a portion thereof associated with said coolingcompartment for cooling the contents of said cooling compartment to atemperature above freezing, said secondary refrigerating apparatushaving a refrigerant passage extending along the top of said coolingcompartment, and means transferring alimited amount of heat from saidsecondary evaporator to said primary evaporator for maintaining saidsecondary evaporator at a relatively higher temperature than saidprimary evaporator.

15. A refrigerating machine comprising a heat insulated cooling,compartment and a heat insulated freezing compartment, said compartmentsbeing mounted in separable superposed relationship yvith the exteriorvertical walls thereof arranged in alignment, means including aperipheral flange extending about the edge of one of said compartmentsadjacent the other of said compartments .for preventing lateraldisplacement between said compartments, means including arefrigerantevaporator having a portion thereof associated with saidfreezing compartment for cooling the, contents thereof to a relativelylow temperature, means including a second refrigerant evaporator havinga portion thereof associated with said cooling compartment for coolingthe contents thereof to' a temperature above freezing, and meansincluding a portion of the first mentioned evaporator for abstractingheat from refrigerant contained in said second evaporator.

16. A refrigerator comprising a heat insulated 'cablnet means fordividing the interior of said cabinet into a plurality of food storagecompartments to be cooled to different temperatures, means including aprimary refrigerating system for cooling one of said compartments to arelatively low temperature, means including a secondary refrigeratingsystem for cooling the other of said compartments to a relatively highertemperature, and means including a portion of said I primaryrefrigerating system and a portion of said secondary refrigeratingsystem arranged in heat exchange relationship and forming at least aportion of said dividing means for transferring heat from said secondaryrefrigerating system to said primary refrigei ating system.

17. A refrigerator comprising a heat insulated cabinet, means fordividing the interior of said cabinet into a plurality of food storagecompartments to be cooled to different temperatures, means including aprimary refrigerating system for cooling one of said. compartments to arelatively low temperature, means including a secondary refrigeratingsystem for cooling the other of said compartments to a relatively'highertemperature, and means including a portion of said primary refrigeratingsystem forming at least a portion of said dividing means fortransferring heat from said secondary refrigerating system to 5 saidprimary refrigerating system.

18. A refrigerator comprising a heat insulated cabinet, means fordividing the interior of said cabinet into a plurality of food storagecompartments to be cooled to different temperatures,

10 means including a primary refrigerating system for cooling one ofsaid compartments to a relatively low temperature, means including asecondary refrigerating system for cooling the other of aid compartmentsto a relatively higher temper lture, and means including a portion ofsaid secondary refrigerating system forming at least a portion of saiddividing means for transferring heat from said secondary refrigeratingsystem to said primary refrigerating system.

CHRISTIAN STEENSTRUP.

